Cooling Pump for Internal Combustion Engine and Cooling System Using the Cooling Pump

Abstract

A cooling pump for an internal combustion engine and a cooling system including the pump. The pump is driven by an electrically-operated motor so as to rotate in a positive direction for supplying cooling water in a reservoir tank to the engine and in a reverse direction for returning the cooling water in the engine to the reservoir tank. The cooling system includes a controller that is coupled with the motor of the pump and generates a first control signal for operating the motor to rotate the pump in the reverse direction so as to return the cooling water in the engine to the reservoir tank and generates a second control signal for operating the motor to rotate the pump in the positive direction so as to supply the cooling water in the reservoir tank to the engine, on the basis of an operating condition of the engine.

1 . A cooling pump for an internal combustion engine, comprising:
 an electrically-operated motor;   a pump impeller that is driven by the motor so as to rotate in a positive direction and a reverse direction; and   a control device coupled with the motor, the control device operating the motor to rotate the pump impeller in the positive direction for supplying cooling water to the engine and rotate the pump impeller in the reverse direction for discharging the cooling water from the engine, in response to a control signal based on an operating condition of the engine.   
   
   
       2 . The cooling pump as claimed in  claim 1 , wherein the control device operates the motor to rotate the pump impeller in the reverse direction for discharging the cooling water from the engine when a temperature of the cooling water in the engine in a start-up state is not more than a first preset value, and rotate the pump impeller in the positive direction for supplying the cooling water to the engine when the temperature of the engine is more than the first preset value. 
   
   
       3 . The cooling pump as claimed in  claim 1 , wherein the control device operates the motor to rotate the pump impeller in the reverse direction for discharging the cooling water from the engine until a time elapsed from start-up of the engine reaches a predetermined value, and rotate the pump impeller in the positive direction for supplying the cooling water to the engine when the time elapsed from start-up of the engine exceeds the predetermined value. 
   
   
       4 . The cooling pump as claimed in  claim 1 , wherein the control device operates the motor to rotate the pump impeller in the reverse direction for discharging the cooling water from the engine when a temperature of the cooling water in the engine in a start-up state is not more than a first preset value, and rotate the pump impeller in the positive direction for supplying the cooling water to the engine when the temperature of the cooling water in the engine in a start-up state is more than the first preset value and a time elapsed from start-up of the engine exceeds a predetermined value. 
   
   
       5 . The cooling pump as claimed in  claim 1 , wherein the control device operates the motor to rotate the pump impeller in the reverse direction for discharging the cooling water from the engine when a temperature of the cooling water in the engine in a stop state is not more than a first preset value. 
   
   
       6 . A cooling system for an internal combustion engine, comprising:
 a reservoir tank that stores cooling water for cooling the engine;   a pump that is driven by an electrically-operated motor so as to rotate in a positive direction for supplying the cooling water in the reservoir tank to the engine and in a reverse direction for returning the cooling water in the engine to the reservoir tank; and   a controller coupled with the motor, the controller generating a first control signal for operating the motor to rotate the pump in the reverse direction so as to return the cooling water in the engine to the reservoir tank and generating a second control signal for operating the motor to rotate the pump in the positive direction so as to supply the cooling water in the reservoir tank to the engine, on the basis of an operating condition of the engine.   
   
   
       7 . The cooling system as claimed in  claim 6 , wherein the controller generates the first control signal when a temperature of the cooling water in the engine in a start-up state is not more than a first preset value, and generates the second control signal when a temperature of the engine is more than the first preset value. 
   
   
       8 . The cooling system as claimed in  claim 6 , wherein the controller generates the first control signal until a time elapsed from at start-up of the engine reaches a predetermined value, and generates the second control signal when the time elapsed from start-up of the engine exceeds a predetermined value. 
   
   
       9 . A cooling system for an internal combustion engine, comprising:
 a reservoir tank that stores cooling water for cooling the engine;   a pump that is driven by an electrically-operated motor so as to rotate in a positive direction for supplying the cooling water in the reservoir tank to the engine and in a reverse direction for returning the cooling water in the engine to the reservoir tank;   a radiator that cools the cooling water heated while flowing in the engine;   a cooling water passage that allows communication between the reservoir tank and the pump via the radiator;   a bypass passage that allows communication between the reservoir tank and- the pump to bypass the radiator, the bypass passage having one end connected with the reservoir tank and the other end connected with the cooling water passage between the radiator and the pump,   a thermostatically-operated valve that is disposed at a connection between the cooling water passage and the other end of the bypass passage, the thermostatically-operated valve being operative on the basis of a temperature of the cooling water; and   a controller coupled with the motor, the controller generating a first control signal for operating the motor to rotate the pump in the reverse direction for returning the cooling water in the engine to the reservoir tank via the bypass passage when a temperature of the cooling water in the engine in a start-up state is not more than a first preset value, the controller generating a second control signal for operating the motor to rotate the pump in the positive direction so as to supply the cooling water in the reservoir tank to the engine when a temperature of the engine is more than the first preset value.   
   
   
       10 . The cooling system as claimed in  claim 9 , wherein the thermostatically-operated valve is operative to open the cooling water passage and close the bypass passage for supplying the cooling water to the engine through the radiator in the cooling water passage when the temperature of the cooling water in the engine is more than the second preset value during rotation of the pump in the positive direction. 
   
   
       11 . The cooling system as claimed in  claim 9 , wherein the thermostatically-operated valve is operative to close the cooling water passage and open the bypass passage for supplying the cooling water to the engine through the bypass passage when the temperature of the cooling water in the engine is more than the first preset value and not more than the second preset value during rotation of the pump in the positive direction. 
   
   
       12 . The cooling system as claimed in  claim 9 , further comprising a return passage that allows communication between the reservoir tank and the engine and returns the cooling water that circulates the engine during the positive rotation of the pump, to the reservoir tank, wherein a first communication port through which the return passage is communicated with the reservoir tank is placed in a height position higher than a second communication port through which the cooling water passage is communicated with the reservoir tank, and a third communication port through which the bypass passage is communicated with the reservoir tank is placed in a height position substantially same as the second communication port or in a height position lower than the second communication port. 
   
   
       13 . The cooling system as claimed in  claim 9 , further comprising a return passage that allows communication between the reservoir tank and the engine and returns the cooling water that circulates the engine during the positive rotation of the pump, to the reservoir tank, and a check valve that allows the cooling water to flow from the return passage into the reservoir tank, the check valve being disposed at a first communication port through which the return passage is communicated with the reservoir tank. 
   
   
       14 . The cooling system as claimed in  claim 9 , further comprising a flow control valve that-is disposed in the cooling water passage between the pump and the thermostatically-operated valve, the flow control valve being operative to control an amount of the cooling water. 
   
   
       15 . The cooling system as claimed in  claim 9 , further comprising a communication passage that communicates the pump and the engine with each other, the communication passage being branched into a high-temperature side passage and a low-temperature side passage which are connected to a high-temperature portion of the engine and a low-temperature portion of the engine, respectively, and a directional control valve that is operative to distribute a flow of the cooling water between the high-temperature side passage and the low-temperature side passage on the basis of an operating condition of the engine. 
   
   
       16 . The cooling system as claimed in  claim 15 , wherein when a temperature of the cooling water in one of the high-temperature portion and the low-temperature portion of the engine in a start-up state is not more than the first preset value, the controller generates the first control signal and a third control signal for controlling the directional control valve so as to return the cooling water in the one of the high-temperature portion and the low-temperature portion of the engine to the reservoir tank, and when the temperature of one of the high-temperature portion and the low-temperature portion of the engine is more than the first preset value, the controller generates the second control signal and a fourth control signal for controlling the directional control valve so as to supply the cooling water in the reservoir tank to the one of the high-temperature portion and the low-temperature portion of the engine.